


The Only One In The World (Roughly Speaking)

by merrymarinerrevengesong



Category: Sherlock (TV)
Genre: Gen, Genderswap, Girls with Guns, sort of genderswap?, surprise!twin
Language: English
Status: In-Progress
Published: 2011-12-30
Updated: 2011-12-30
Packaged: 2017-10-28 11:48:16
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,517
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/307566
Author URL: https://archiveofourown.org/users/merrymarinerrevengesong/pseuds/merrymarinerrevengesong
Summary: <blockquote class="userstuff">
              <p>In which Sherlock's twin sister appears, John is inexplicably jealous and Harry Watson's backstory is revealed.</p>
            </blockquote>





	The Only One In The World (Roughly Speaking)

**Author's Note:**

> This fic is entirely inspired by a beautiful drawing of Sherlock and his twin sister sizing each other up, sidekicks near in tow. How's a girl suposed to resist?
> 
> http://yskwwww.tumblr.com/post/14968239048/genderbending-if-sherlock-is-mixed-twins
> 
> Thank you ever so much to yskwwww for the kind permission to fic my little heart out.

John Watson was utterly taken aback to learn that Sherlock Holmes had a sibling. Somehow Sherlock had always seemed to him to be too volatile and otherworldly to have a family. After all, a family tethered a man and watching Sherlock in one of his manic whirlwinds or listless slumps, it seemed as though Sherlock hadn’t been tethered by anything in his existence. Perhaps the problem with the notion ‘Sherlock’s family’ was actually the problem of the notion of ‘Sherlock’s childhood’. Which is to say, it was almost impossible for John to imagine a young Sherlock, innocent and open to the wonders of the world, and therefore any sort of family life John tried to summon up was very bleak indeed. So one day, when it was mentioned in conversation quite casually that Sherlock had not only a sibling, but a twin sister, John simply refused to countenance the idea. That he should learn such news from Harry Watson rather than Sherlock himself only acted to deepen his disbelief.

 

“Oh, Goldwine was in touch earlier this week, by the way. She’s lovely, don’t know why you haven’t mentioned her before, John.” Harry’s chiding was playful and light, and very clearly said _I know exactly why you haven’t mentioned her before, you sly dog_. Something about the way Harry quirked her eyebrow also told John that she thought she had a very good chance with this young lady; it was a look he remembered well from his teenaged years, when Harry had thought it great fun to ‘turn’ every girl he so much as looked at. After the first dozen he just stopped looking.

“I _actually_ have no idea who you’re talking about.” Retorted John, spearing an unsuspecting cherry tomato rather more violently than he’d intended.

“Goldwine Holmes, Sherlock’s twin sister.”

“Sherlock doesn’t have a sister, Harry, just a brother.”

Harry laughed, “No, he definitely has a sister, she’s a Holmes for sure.”

John clenched his teeth, “Harry, I’m sure there are plenty of Holmeses who share relatively little DNA with Sherlock. It’s a common enough name. I think I’d know if _my friend_ had a sister.”

And _that_ was why John always lost poker matches against Harry. Impossible not to be utterly aggravated by something she said or did (or seduced) a decade ago and completely show his hand at the crucial moment.

She smirked over the rim of her wine glass. “Calm down, I’m not going to steal your _boy_ friend,” She teased, taking a sip, “to whom Goldwine is definitely related, by the way. Did the whole mind reading thing on me. Bloody creepy, don’t know how you live under the same roof as him. Besides, she’s the spitting image.”

John huffed, “I’m sorry, but I think Sherlock would have mentioned a twin sister at some point in the year and a half that I’ve known him.”

Harry fixed him with a look equal parts exasperation at her brother’s childish jealousies and annoyance that her fun had been ruined. She shrugged carelessly, “Fine, whatever, forget I said anything. You have any idea what you’re getting Mum for Christmas this year?”

 

\---

 

John didn’t return to Baker Street immediately after dinner with Harry. He delayed as long as possible, wandering slowly around Tescos, visiting every isle twice, planning the weeks meals in his head as he went. How on earth could Sherlock have failed to mention he had a twin sister? Particularly as John _specifically_ asked him if there were any female Holmes children after arriving home from a particularly deep pint with Lestrade last year. Although, come to think of it, if anyone asked him whether he had a sister, he usually told them to fuck off. Not least of all because Harry was an incorrigible flirt who delighted in winding him up by any means possible even when she had no interest in his rugby team.

“PIN or sign, love?”, John was woken from his reverie by the middle-aged woman behind the checkout.

“Oh…er, PIN, thanks. Sorry, I was a million miles away.”

She smiled softly at him, “Fight with the missuss?”

John smiles awkwardly and gathers up his shopping bags, “Something like that, yeah.” A fight with Sherlock is a lot closer to how John imagines a fight with a wife would feel than any fight he’s had with a best friend. Sherlock’s almost petulant inability to follow social convention in their friendship, as well as every other area of his life, had stopped bothering John a long time ago.

 

\---

 

“You’re late.”

There was no preamble to this observation; Sherlock stated it simply to lead into his inevitable deduction. “I see Harry’s drinking again, then.”

John dumped the shopping bags on the kitchen table with more force than was strictly necessary. The old table shuddered, earning John a warning hum from Sherlock for the potential damage caused to his experiment.

“No. Well, yes, she is, but that’s not why I’m late.”

“Of course it is. You return from dinner with your alcoholic sister a full hour after it finished, limping slightly with fistfuls of unnecessary purchases from Tescos. You’re upset about something; Harry’s drinking again.”

“Wrong.” John retorts mockingly as he puts the kettle on. “Y’know, _food_ isn’t unnecessary, Sherlock. Even if you’re happy half killing yourself with malnutrition, I do like three square meals a day.”

“Irrelevant. You’re upset. Specifically, you feel betrayed. Only Harry’s drinking does that to you. I am right in my deduction, why on earth are you resisting me?”

At this, Sherlock’s back straightened and he went very still.

“Oh.” He said softly under his breath, meeting john’s eyes for the first time that evening. “There’s something more. Something happened at dinner with your sister, yes, but not related to her drinking.”

Finally he rose to his feet and crossed the kitchen to the counter against which John was leaning. He was dressed as he generally was, in a suit, shirt cuffs rolled up to his elbows. Now that he had a small puzzle to put his mind to, there was something slow and predatory in the way he moved, each step and gesticulation precise and efficient.

“It’s me isn’t it? You’re angry at me… but why…”

John felt suddenly uncomfortable under the intensity of Sherlock’s gaze. It wasn’t the first time he’d been in this position, even in the middle of an argument, but unlike every other infuriatingly inconsiderate and insensitive thing John had taken umbrage with, this time he wasn’t even sure he had anything to be angry about.

He huffed his deflation and turned his back on Sherlock to make tea.

“It’s nothing, just something Harry said about you.”

Sherlock sensed John wasn’t angry anymore and relaxed, “Is she still insinuating we’re lovers?”

“Yeah, but that wasn’t it. She seemed to think she’d had a visit form your twin sister.” He said, turning around to hand Sherlock his tea. For a moment Sherlock simply froze, his mouth slightly open and eyes not quite focused on John.

John felt his own mouth fall open in sympathy but found he couldn’t work his vocal chords enough to stutter his surprise. Sherlock regained his composure quickly and took the proffered tea without thanks.

“Hmmmnn, yes I did wonder when Goldwine might… show up.”

Being the flat-mate, colleague and friend of Sherlock Holmes, John frequently found himself in situations where worlds failed him utterly. But this, _this_ was surely a new level of speechlessness. He stood watching Sherlock work on his experiment for a full two minutes before he could say anything.

“You have a twin?” John asked dumbly. “That you never mention, never see? That _Mycroft_ never mentions?”

Sherlock glanced up from his experiment once more, apparently surprised that John is still in the room. “Yes well, the relationship is somewhat strained.”

“My relationship with Harry’s _strained_ I don’t bloody well act as though she was stillborn.” John explodes.

Sherlock shakes his head slightly, “Really John, why are you so upset? You're not the person whose estranged twin has walked back into his life for the first time in almost a decade.”

At that John decided to call it a night, slamming as many doors on his way to his bedroom as he found convenient. Later, when he was lying in bed unable to sleep he wondered about Sherlock’s unusually emotionally perceptive question. He couldn’t say why he felt so hurt by Sherlock’s staying silent about his twin, but he felt it had something to do with the painful image he’d built up over the months of Sherlock as a young boy. Alone, teased, incredibly vulnerable in that period of time it must’ve taken for him to develop the prickly persona he currently used as a defense against taunts. John shifted uncomfortably, there was something else, something more. A fleeting impression swelled up in him mind unbidden, of a cold night, too distant police sirens, and a feeling of helpless terror that filled his stomach over a year ago when his gun weighed heavy in his hand and Sherlock, in another building, lifted a pill to his lips.

**Author's Note:**

> Goldwine's name was chosen purely for it's Middle English origin, which it shares with Sherlock and Mycroft, as far as I can tell.
> 
> I haven't actually plotted too far in advance, so ratings/ pairings may change.


End file.
